https://ej-eng.org/index.php/ejeng/issue/feedEuropean Journal of Engineering and Technology Research2025-02-11T21:16:42+01:00Editor-in-Chiefeditor@ej-eng.orgOpen Journal SystemsEuropean Journal of Engineering and Technology Researchhttps://ej-eng.org/index.php/ejeng/article/view/3217On the Wavelength and Frequency of the Actual Chladni Patterns Visualized on Square Plates2024-10-25T23:11:08+02:00Barenten Suciusuciu@fit.ac.jpSota Kariminemcm23101@bene.fit.ac.jpNaofumi Yamazumis21e2070@bene.fit.ac.jpYuki Mitsuishis19e2054@bene.fit.ac.jp<p class="p1">In this study, Chladni patterns are visualized on square plates made of various metallic materials in the domain of low frequencies around the first flexural resonant peak. Using the membrane and the thin plate models, the undamped and damped natural frequency of the square panel is explicitly expressed versus the mean wavelength of the bending vibration. The wavelength of the idealized Chladni figures is evaluated for linear and curvilinear nodal lines relevant to our experiments. Significant discrepancy between the computed and measured frequencies is corrected based on the wavelength evaluation of the actual Chladni figures, done by considering the cutting and rounding of the nodal lines near the plate edges and near the central point of excitation. Such model able to link the shape of the actual nodal lines with the excitation frequency is useful for the motion control of micro-particles on the vibrating plate.</p>2025-01-05T00:00:00+01:00Copyright (c) 2025 Barenten Suciu, Sota Karimine, Naofumi Yamazumi, Yuki Mitsuishihttps://ej-eng.org/index.php/ejeng/article/view/3206Behavior of Anticorrosive Efficiency of Conventional Concrete Reinforced with Stainless Steel in the Presence of 5% CaCl22025-01-09T21:13:53+01:00Brenda Paola Baltazar-Garcíapao.baltazar.08@gmail.comLaura Landa-Ruizlalanda@uv.mxRene Crochealdlanda@uv.mxDavid Lozanodlozano@uv.mxJosé Reyesalbreyes@uv.mxGabriel Santosgasantos@uv.mxCe Tochtli Méndezcmendez@uv.mxFrancisco Estupiñanfrancisco.estupinan@uanl.edu.mxCitlalli Gaonacitlalli.gaonatbr@uanl.edu.mxMiguel Angel Baltazar-Zamorambaltazar@uv.mx<p class="p1">This project evaluated the behavior of the electrochemical corrosion resistance of AISI 304 Stainless Steel as reinforcement in conventional concrete, elaborated based on the method ACI 211.1, with a water/cement = 0.65 ratio. The samples were in the presence of water and a 5% CaCl<sub><span class="s1">2 </span></sub>solution for more than 160 days, the first environment representing a control medium and the second representing an aggressive medium. On the other hand, the electrochemical technique of linear polarisation resistance (Rp) was implemented for the determination of the intensity of corrosion current I<sub><span class="s1">corr </span></sub>and the measure of corrosion potencial E<span class="s1">corr</span>, in accordance with the ASTM C-876-15 method. As a result, E<sub><span class="s1">corr </span></sub>and I<span class="s1">corr </span>values were obtained, demonstrating a better performance against corrosion in the presence of a high level of chlorides when using AISI 304 Stainless Steel.</p>2025-01-06T00:00:00+01:00Copyright (c) 2025 Brenda Paola Baltazar-García, Laura Landa-Ruiz, Rene Croche, David Lozano, José Reyes, Gabriel Santos, Ce Tochtli Méndez, Francisco Estupiñan, Citlalli Gaona, Miguel Angel Baltazar-Zamorahttps://ej-eng.org/index.php/ejeng/article/view/3225Blue-Shifting Photoluminescence in HFCVD-Deposited Tin-Doped SRO Films2025-02-06T21:17:12+01:00Daniel Diaz Tapiadaniel.diazta@alumno.buap.mxCrisoforo Morales Ruizcrisomr@yahoo.com.mxReina Galeazzi Isasmendiingquim25@gmail.comHéctor Pérez Ladrón de Guevarahpldg@yahoo.com.mxRoberto Portilloportilloreyes@yahoo.comRoman Romano Trujilloroman.romano@correo.buap.mxAntonio Coyopolacoyopol@gmail.comEnrique Rosendoenrique171204@gmail.com<p class="p1">Silicon-rich oxide (SRO) films doped with tin (Sn-SRO) were successfully deposited using hot filament chemical vapor deposition (HFCVD), with tin-doped SBA-15 as the solid source material. SBA-15 acted as a protective layer, ensuring thermal stability and enabling the controlled incorporation of tin into the SRO films. Structural and optical analyses, including Fourier- transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and photoluminescence (PL), were performed to evaluate the films. FTIR revealed SiO<span class="s1">2 </span>absorption peaks and Si-O-Sn bond formation, confirming the progressive incorporation of tin. TEM demonstrated the formation of silicon nanocrystals (Si-NCs), with decreasing size as tin concentration increased. This size reduction was correlated with enhanced PL intensity and a blue shift, attributed to stronger quantum confinement effects. These analyses provide a comprehensive understanding of the structural and optical behavior of Sn-doped SRO films. These findings highlight the potential of Sn-SRO films for optoelectronic applications, where controlling light emission and crystallinity is essential.</p>2025-01-30T00:00:00+01:00Copyright (c) 2025 Daniel Diaz Tapia, Crisoforo Morales Ruiz, Reina Galeazzi Isasmendi, Héctor Pérez Ladrón de Guevara, Roberto Portillo, Roman Romano Trujillo, Antonio Coyopol, Enrique Rosendohttps://ej-eng.org/index.php/ejeng/article/view/3210Construction of Machines Capable of Extracting Energy from the Forces of Nature with Over-unity Efficiencies is Made Possible2025-02-11T21:16:42+01:00Suniti Kumar Ghoshalsunitikghoshal@gmail.com<p class="p1">The possibility of constructing machines capable of extracting energy from the forces of nature with N > 1 efficiencies by making use of novel energy-harvesting ideas has been brought to light. The electrostatic, magnetic and electromagnetic forces have been identified as the promising ones to meet this objective. The working of one of such machines is based on the simple idea of allowing both the charging and discharging currents of a capacitor to pass through a DC motor uni-directionally repetitively. The second kind of machine, capable of extracting energy from magnetic forces, makes use of both attractive and repulsive forces between pole pieces of permanent and electromagnets. This machine is capable of generating energy with N > 1 efficiencies as it effectively extracts energy from both the attractive and repulsive magnetic forces. The machines of the third kind take advantage of Barlow’s motor, which, when connected in series with a DC motor and a DC current is passed through them the Barlow’s motor generates energy without the consumption of any electrical power. The possible ways of improving the efficiency of the machines are discussed.</p>2025-01-17T00:00:00+01:00Copyright (c) 2025 Suniti Kumar Ghoshal